Scam air brakes operation trailer air brakes are operated by the tractor air supply through series of relay and check valves. when braking is desired, theRoller skates are shoes, or bindings that fit onto shoes, that are worn to enable the wearer to roll along on wheels. the first roller skate was effectively an ice skate with wheels replacing the blade. later the “quad” style of roller skate became more popular consisting of four wheels arranged in the same configuration as typical car Deluxe hookandloop straps hold these light weight lawn aerator shoes to your feet. each step presses dozen in. metal spikes into hardpacked soil and denselypacked turf. thousands